JP2002151745A - Semiconductor device - Google Patents

Abstract

[PROBLEMS] To reduce the size and improve the luminous efficiency of a light emitting element. A ball (5a) overlaps a second wiring pattern (2), and an end (5b) of a wire (5) overlaps an upper surface of a light emitting diode (4). Since the end 5b of the wire 5 is very thin, the arch of the wire 5 pulled out from the electrode on the upper surface of the light emitting diode 4 can be reduced, and the size of the semiconductor element can be reduced. The electrodes on the upper surface of the light emitting diode 4 are:
It is formed in a rectangular shape elongated in the direction in which the wire 5 extends. For this reason, the open area of the upper surface of the light emitting diode 4 is wide, and more light is emitted from the upper surface, and the light emitting efficiency of the light emitting diode 4 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a light emitting diode mounted on a substrate.

[0002]

2. Description of the Related Art As a conventional apparatus of this kind, for example, there is one as shown in FIG. In this device, a first wiring pattern 101 and a second wiring pattern 102 are formed on a substrate 103, and a light emitting diode 10 is formed on the first wiring pattern 101.
4 is mounted and adhered, and the wire 1 is formed by wire bonding from the light emitting diode 104 to the second wiring pattern 102.
05, and the light emitting diode 104 is formed on the substrate 103.
The wires 105 are sealed with a resin 106.

[0003]

When wire bonding from the light emitting diode 104 to the second wiring pattern 102, first, a ball 105a is formed at the tip of a bonding wire (Au wire or the like), and as shown in FIG. Ball 105a to the electrode 1 on the upper surface of the light emitting diode 104.
07, the wire 105 is subsequently extended from the light emitting diode 104 to the second wiring pattern 102, and the end 105b of the wire 105 is
It is bonded to the wiring pattern 102. Therefore,
The ball 105 a at the tip of the wire 105 overlaps the light emitting diode 104.

However, the diameter of the ball 105a is as large as about 100 μm, and the height of the arch of the wire 105 is about 150 μm, which makes it difficult to miniaturize the semiconductor device.

As shown in FIG. 7, the electrode 107 is formed in a substantially square shape, and the length of one side of the electrode 107 is
The electrode 107 is set to about 100 μm which is almost the same as the diameter of
Are suitable for bonding the ball 105a.

However, the electrode 107 having such a shape and size covers the upper surface of the light emitting diode 104 in a wide range. For this reason, most of the light from the upper surface was blocked, and the luminous efficiency of the light emitting diode 104 was reduced.

In Japanese Utility Model Laid-Open No. 6-7263, a recess is provided in a substrate, and a light emitting diode is arranged in the recess.
There is disclosed a technique for reducing the thickness of the device. However, in this case, the processing steps of the substrate become complicated and the cost of the substrate increases.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a semiconductor device capable of reducing the size and improving the luminous efficiency of a light emitting element.

[0009]

In order to solve the above-mentioned problems, the present invention comprises forming first and second wiring patterns on a substrate, mounting a light emitting diode on the first wiring patterns,
The second wiring pattern and the light emitting diode are connected by reverse wire bonding from the second wiring pattern to the light emitting diode.

According to the present invention having such a configuration, the light emitting diode is connected to the second wiring pattern by reverse wire bonding from the second wiring pattern to the light emitting diode. At the time of the reverse wire bonding, first, a ball is formed at the tip of a bonding wire (Au wire or the like), and the ball is bonded on the second wiring pattern. Then, the end of the wire is bonded to the electrode on the upper surface of the light emitting diode. Therefore, the ball overlaps the second wiring pattern, and the end of the wire overlaps the upper surface of the light emitting diode. Since the ends of the wires are very thin, the arch of the wires drawn from the electrodes on the upper surface of the light emitting diode can be reduced, and the size of the semiconductor element can be reduced.

In the present invention, the electrode of the light emitting diode to which the wire bond is bonded has an elongated shape in the extending direction of the wire.

Since the electrode of the light emitting diode is connected not to the ball at the tip of the wire but to the end of the wire, the electrode can be formed in an elongated shape with a small area.
For example, the electrodes can be formed in a rectangle, trapezoid, triangle, or the like. When the area of the electrode is reduced, the open area of the upper surface of the light emitting diode is widened, a large amount of light is emitted from the upper surface, and the luminous efficiency of the light emitting diode is improved.

Further, in the present invention, the diameter of the wire formed by the reverse wire bonding is from 20 μm to 23 μm.
m.

Since the end of the wire becomes smaller as the diameter of the wire becomes smaller, the electrode on the upper surface of the light emitting diode can be made smaller and the luminous efficiency can be improved. However, in order to maintain the practical strength of the wire. In this case, the diameter of the wire is preferably set to 20 μm to 23 μm.

Further, in the present invention, the arch of the wire formed by the reverse wire bonding has a height of 30 μm to 50 μm from the upper surface of the light emitting diode.

The lower the arch of the wire is, the smaller the semiconductor device is, but the more likely it is that the wire contacts the edge of the light emitting diode and breaks. Therefore, the height of the arch of the wire is set to 30 μm from the upper surface of the light emitting diode. ~
It is better to set it to about 50 μm.

Further, in the present invention, the first and second wiring patterns are embedded in the surface of the substrate.

By embedding the first and second wiring patterns on the surface of the substrate in this manner, the semiconductor device can be reduced in size and reduced in size by the thickness of the wiring pattern.

Further, in the present invention, the height of the light emitting diode is 100 μm to 190 μm.

Considering the strength of the light emitting diode, its height (thickness) is preferably set to 100 μm or more. Considering the height of other chip components (capacitors and resistors), the height (thickness) is preferably set to 190 μm or less.

Further, in the present invention, the light emitting diode is sealed on the substrate with a resin.

By sealing the light emitting diode with the resin as described above, the durability of the semiconductor device is improved.

[0023]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a side view showing an embodiment of the semiconductor device of the present invention. In the semiconductor device of the present embodiment, the first wiring pattern 1 and the second wiring pattern 2 are formed on a substrate (PWB; Pr
inted writing Board) 3 and light emitting diode 4
Is adhered on the first wiring pattern 1 with the conductive paste 8, and the wire 5 is formed by reverse wire bonding from the second wiring pattern 2 to the light emitting diode 4.
The light emitting diode 4 and the wire 5 are sealed with a resin 6. The resin 6 protects the semiconductor device and enhances its durability, and is formed by a casting method or a transfer molding method.

From the second wiring pattern 2 to the light emitting diode 4
Reverse wire bonding is performed in the following procedure. First,
The tip of a bonding wire (Au wire or the like) is melted to form a ball 5a, and the ball 5a is bonded onto the second wiring pattern 2. Subsequently, the wire 5 is extended from the second wiring pattern 2 to the upper surface of the light emitting diode 4, and the end 5b of the wire 5 is bonded to the electrode 7 on the upper surface of the light emitting diode 4, as shown in FIG. When the wire 5 is extended, the diameter of the wire 5 is set to 20 μm to 23 μm as shown in FIG. 3, and the height of the arch of the wire 5 with respect to the upper surface of the light emitting diode 4 is set to 30 μm to 5 μm.
Set to 0 μm.

The ball 5 a overlaps the second wiring pattern 2, and the end 5 b of the wire 5 overlaps the upper surface of the light emitting diode 4. Since the end 5b of the wire 5 is very thin, the arch of the wire 5 pulled out from the electrode 7 on the upper surface of the light emitting diode 4 can be reduced, and the size of the semiconductor element can be reduced.

In the conventional device shown in FIG. 6, since the ball 105a is bonded to the electrode 107 on the upper surface of the light emitting diode 104, the height of the arch of the wire 105 with respect to the upper surface of the light emitting diode 104 is about 150 μm. In contrast, in the device of the present embodiment,
Since the height of the arch of the wire 5 with respect to the upper surface of the light emitting diode 4 is 30 μm to 50 μm, the entire device is 100
μm or less.

As shown in FIG. 2, the electrode 7 on the upper surface of the light emitting diode 4 is formed in a rectangular shape elongated in the direction in which the wire 5 extends. The shape of the electrode 7 is set in consideration of the shape of the end 5b of the wire 5. Assuming that the diameter of the wire 5 is d (= 20 μm to 23 μm), the width of the end 5 b is about 4 d (≒ 100 μm),
The vertical width of b is about 2d (≒ 50 μm). This end 5b
The width of the electrode 7 is about 100 μm according to the shape and size of
The vertical width is set to about 50 μm.

Such an electrode 7 is half the size of the electrode 106 in the conventional device shown in FIG. For this reason, compared with the conventional device, the open area of the upper surface of the light emitting diode 4 is wider, and more light is emitted from this upper surface, and the light emitting efficiency of the light emitting diode 4 is improved.

In order to widen the open area of the upper surface of the light emitting diode 4, the electrode 7 is formed in an elongated trapezoidal shape or a triangular shape in the extending direction of the wire 5, and the electrode 7 is formed with the shape of the end 5 b of the wire 5. It may be closer to the size.

Further, as the diameter of the wire 5 becomes smaller, the end 5b of the wire 5 becomes smaller.
Although the light emitting efficiency can be improved by reducing the size of the electrode 7 on the upper surface, the diameter of the wire 5 is set to 20 μm to 23 μm in order to maintain the strength of the practical wire 5.

Further, the lower the arch of the wire 5 is,
Although the size of the semiconductor device is reduced, the possibility that the wire 5 comes into contact with the edge of the light emitting diode 4 and breaks is increased. Therefore, the height of the arch of the wire 5 is set to about 30 μm to 50 μm from the upper surface of the light emitting diode 4. I have.

FIG. 4 shows a modification of the semiconductor device of this embodiment. Here, after the first and second wiring patterns 1 and 2 are formed on the substrate 3, the substrate 3 is subjected to a press process, and the first and second wiring patterns 1 and 2 are embedded in the surface of the substrate 3. Thereby, the semiconductor device can be reduced in size and downsized by the thickness of the first and second wiring patterns 1 and 2.

The height (thickness) of the light emitting diode 4 is set to 100 μm to 190 μm.

The graph of FIG. 5 shows the non-breaking rate of the light emitting diode with respect to the height of the light emitting diode. As the light emitting diode 4 becomes lower (thinner), the light emitting diode 4 is more easily broken by the reverse bond wire. For this reason,
It is necessary to limit the height of the light emitting diode 4 to increase the non-breaking rate, that is, the remaining rate of the normal portion where the light emitting diode 4 has not broken, and to reduce the defective rate of the semiconductor device. Here, if the non-cracking rate of at least 90% is achieved, the defect rate of the semiconductor device becomes almost 0%. Therefore, the minimum height of the light emitting diode 4 was set to 100 μm so that a non-cracking rate of 90% was achieved.

The height of components such as chip resistors and chip capacitors is set to about 3.5 mm.
It is desirable that the height of the semiconductor device of the present embodiment be suppressed to 5 mm or less. Here, the thickness of the substrate 3 is set to 100 μm,
Assuming that the maximum height of the arch of the wire 5 is 50 μm and the thickness of the resin 6 on the wire 5 is 10 μm, the sum of them becomes 160 μm. Therefore, the maximum height of the light emitting diode 4 is set to 190 μm so that the height of the semiconductor device can be suppressed to 3.5 mm or less.

The present invention is not limited to the above embodiment, but can be variously modified. For example, another metal may be applied as the material of the wire. Further, the arrangement of the first and second wiring patterns and the light emitting diodes may be appropriately changed.

[0038]

As described above, according to the present invention, the second
The second wiring pattern and the light emitting diode are connected by reverse wire bonding from the wiring pattern to the light emitting diode. In this case, the ball overlaps the second wiring pattern,
The end of the wire overlaps the top surface of the light emitting diode. Since the end of the wire is very thin, the arch of the wire pulled out from the electrode on the top of the light emitting diode can be lowered,
The size of the semiconductor element can be reduced.

Further, according to the present invention, not the ball at the tip of the wire but the end of the wire is connected to the electrode of the light emitting diode, so that the electrode can be formed in a narrow and narrow shape with a small area. For example, if the electrodes are rectangular, trapezoidal,
It can be formed in a triangle or the like. When the area of the electrode is reduced, the open area of the upper surface of the light emitting diode is widened, a large amount of light is emitted from the upper surface, and the luminous efficiency of the light emitting diode is improved.

Further, according to the present invention, as the diameter of the wire becomes smaller, the end of the wire becomes smaller, so that the electrode on the upper surface of the light emitting diode can be made smaller and the luminous efficiency can be improved. In order to maintain the strength of the wire, the diameter of the wire is set to 20 μm to 23 μm.

According to the present invention, the lower the arch of the wire is, the smaller the semiconductor device is, but the higher the possibility that the wire comes into contact with the edge of the light emitting diode and breaks is increased. The height is set to about 30 μm to 50 μm from the upper surface of the light emitting diode.

Further, according to the present invention, since the first and second wiring patterns are embedded in the substrate surface, the semiconductor device can be reduced in size and reduced in size by the thickness of the wiring pattern.

According to the present invention, the height of the light emitting diode is 100 μm to 190 μm. Considering the strength of the light emitting diode, its height (thickness) is 100 μm
It is better to set above. Considering the height of other chip components (capacitors and resistors), the height (thickness) is preferably set to 190 μm or less.

Further, according to the present invention, the durability of the semiconductor device is improved by sealing the light emitting diode with a resin.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a semiconductor device of the present invention.

FIG. 2 is a plan view showing the vicinity of the light emitting diode of FIG. 1 as viewed from above.

FIG. 3 is an enlarged side view showing the vicinity of the light emitting diode of FIG. 1;

FIG. 4 is a side view showing a modification of the semiconductor device of the embodiment.

FIG. 5 is a graph showing a non-crack ratio of a light emitting diode with respect to a height of the light emitting diode.

FIG. 6 is a side view showing a conventional semiconductor device.

FIG. 7 is a plan view showing the vicinity of the light emitting diode of FIG. 6 as viewed from above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st wiring pattern 2 2nd wiring pattern 3 board | substrate 4 light emitting diode 5 wire 6 resin 7 electrode 8 conductive paste

Claims (7)

[Claims] A first wiring pattern formed on a substrate; a light emitting diode mounted on the first wiring pattern;
A semiconductor device wherein the second wiring pattern and the light emitting diode are connected by reverse wire bonding from the second wiring pattern to the light emitting diode. 2. The semiconductor device according to claim 1, wherein the electrode of the light emitting diode to which the wire bond is bonded has an elongated shape in a direction in which the wire extends. 3. The semiconductor device according to claim 1, wherein a diameter of the wire formed by the reverse wire bonding is 20 μm to 23 μm. 4. The arch of the wire formed by the reverse wire bonding is 30 μm to 5 μm from the upper surface of the light emitting diode.
4. The method according to claim 1, wherein the height is 0 .mu.m.
The semiconductor device according to any one of the above. 5. The semiconductor device according to claim 1, wherein the first and second wiring patterns are embedded in a surface of the substrate. 6. The light emitting diode has a height of 100 μm to 100 μm.
The semiconductor device according to claim 1, wherein the thickness of the semiconductor device is 190 μm. 7. The semiconductor device according to claim 1, wherein the light emitting diode is sealed on a substrate with a resin.